Statistical correlation of fatigue life of 15MnVN steel notched bar under variable amplitude tension-tension block loading

Variable amplitude tension-tension block loading is repeated and applied to test 15MnVN steel notched bars. The block loading consists of three steps of load increase reaching a peak at the fourth step followed by three steps of load decrease returning to the initial level. The results are presented in terms of the probability distribution function. One of the objectives of this work is to show that the probability distribution correlates well with the fatigue life data of the high-strength low-alloy steel which exhibits the discontinuous strain hardening characteristics and does not have any overload effect. It is shown that the fatigue life and critical accumulated damage data flow the log-normal distribution.